Boiler-tube cleaner



(Ct 1, i935. H, L. STALEY 2,@]l5 @?3 BOILER TUBE CLEANER Filed July 20, 1935 INVENTOR. W U/% 7 Patented Oct. 1, 1935 UNITED STATES PATENT OFFICE 8 Claims.

This invention relates to improvements in a class of tube cleaners adapted to be rotated at high speed, and having a, rotary head upon which are slidably mounted centrifugally acting wings which carry thereon rotatable toothed cutters for removing scale or incrustation from the inner walls of boiler tubes.

More specific objects of my invention are, first, to provide a cleaner for either straight or curved tubes, in which great flexibility is introduced by novel arrangement of parts so that bends in tubes can. be negotiated without lessening the cutting action; second, to provide a cleaner with wings to slide radially and swing freely; third, to provide a cleaner of this type with cutters of new design in which the tendency of the teeth to strike repeatedly at the same point is eliminated.

My invention will be best understood by reference to the accompanying drawing, in which Figure 1 is a side elevation of the tool with one wing expanded indicating the position it assumes as it emerges from the tube; Figure 2 is a sectional front view of Figure 1 on line 2, 2; Figure 3 is a view in perspective of the body member; Figure 4 is a view in perspective of the slidable wing; Figure 5 is a front view of the cylindrically shaped cutters used; Figure 6 is a side elevation of the same cutter; Figure '7 is a front view of the cone shaped cutter which is placed in the most forward position of the cleaner; Figure 8 Is a side elevation of the same device.

The numeral I designates the body of my invention, which consists of a longitudinally extending shaft 3, having a plurality of rectangularly shaped arms 4 projecting radially near one end of the body thereof, the other end being provided with screw connection It for attaching a driving mechanism to the device. The central section of shaft 3 is reduced longitudinally to make the remaining portion conform to the thickness of said projecting arms, the object being to provide an abutting member for the rearward end of slidable wing 5 when the cleaner passes through the end of the tube.

A radially extending recess 7 is provided in projecting arm 4 for the introduction of pin 8, said pin arranged to retain the cleaner in an assembled position. Recess I should be located behind the center of gravity of assembled wing 5 so that when the cleaner passes through the tube, the action of centrifugal force upon center of weight forward of recess 1 will cause the rearward end of the wing to move inwardly behind collar 22, permitting thecleaner to be'easily drawn back into the tube again. A recess 6 should be cut into the shaft portion for cutters I2 so as to permit a closer nesting of the head when in closed position. I prefer that a shoul--v der 26 be located forward of threads I6 to pro vide a stop for collar 22.

Wings 5 of my preferred form being identical, I shall describe one only. In outline it is rectangular, with a longitudinally extending groove 9 out throughout its lower portion. A rectangular slot II! is provided through the forward por- 5 tion of said wing to coincide with groove 9 and arranged to movably engage radially extending arm 4. Slot It should be large enough to permit the wing to slide outwardly and swing freely on said projecting arm 4. Rearwardly of slot Ill, 10 a transverse groove I I is made in the wing for the introduction of cutters I2. Said cutters are retained in position by a headed bolt I3 which is introduced in hole I4 and secured in the wing by means of a threaded section en a ing threads I5. Behind the head of bolt I3 are rotatably mounted two cutters I1 and I8, the forward cutter I8 being conical in shape.

Hole 23 provides housing facilities for pin 8. Said hole is bored partly through the lower wall of hole I4 so that when pin 8 which has a central transverse groove therein, is placed within its receiving hole 23, bolt I 3 will pass through the groove thereof and retain the pin in position.

It is necessary that bolt I3, belocated at one 25 side of the radial line of movement of said wing, and I prefer that it be placed forwardly of projecting arm 4 as related to its direction of rotation to greatly increase the cutting action.

It is obvious that the scale on the wall of the boiler tube resists the forward movement of cutters I2, I! and I8 and that this resisting force is opposite to the direction of the motion of said cutters at the point of contact of the aforesaid cutters and said tube wall. In other words this force is tangent to the surface of the tube at the point of contact and opposite to the direction of travel of said cutters. It is well understood of course, that this resisting force is transmitted from said cutters to the wing 5 through bolt I 3. 4.0

Since wing 5 is free to slide on arm 4, the only driving force which frame I may transmit to said wing, is a force perpendicular to the surface of arm 4 of said frame. Now if bolt I3, which is in reality the center of cutters I 2, I1 and I8 is placed on the line of motion of wing 5, the resisting force on said cutters and .arm will be exactly opposite in direction to the driving force on arm 4.

However, if bolt I3, and therefore the center of said cutters, is placed to one side of the line of motion of wing 5, the resisting force on said cutter and arm is applied at an angle to the driving force on said arm. The resultant force set up by the action of the resisting force .and the driving force will be perpendicular to the tube wall, and will be against the tube Wall if cutters are in front of arm 4 of frame I, or away from the tube wall if said cutters are behind arm 4 of said frame.

It will thus be seen that by placing bolt l3 to one side of the line of motion of wing 5 makes possible as desired, an increase or decrease of cutting pressure on the scale within the tube. This. increase or decrease of cutting pressure is entirely separate from, and in addition to the centrifugal force on said wing.

Cutters l2 and I8 used on this tube cleaner are of an improved design. Instead of-having the points of all the teeth I9 regularly spaced at any cross section perpendicular to the axis of rotation, the teeth are formed by the same angular cutter but cut at unequal tooth depths to make a difference in circular pitch of the teeth so as to eliminate the tendency of the teeth to strike repeatedly at the same point like a knurling tool. In my preferred design of cutters, the base line 20 of the teeth is slightly eccentric to the centrally located hole2l which causes the points of the teeth to have unequal spaces between them. The distance from b to b is greater than the distance from c to c with a gradation'of spaces 7 between these two extremes.

In operation, the cleaner is attached to a prime mover and rotated at high speed. This rotation causes wing 5 to move outwardly by centrifugal action until cutters l2, l1 and 18 come in contact with the scale. Should cutter l3 strike .a heavy piece of scale the forward portion of wing 5 will move inwardly and relieve arm 4 of undue strain. Also should there be a pocket in the tube due to a heat blister, wing 5 possesses such flexibility of movement that the cutters thereon will reach in and remove the scale therein; By permitting wings 5 to swing freely on radially extending arms 4, bends in tubes can be negotiated with great effectiveness and speed in cleaning because the forward and rear cutters are kept in constant contact with the tube and with all strain removed from the cleaner.

Having fully described my invention I claim as new: I

l. A tube cleaner having a revoluble cutter head which comprises a body with radially projecting arms thereon, wings mounted on said projecting arms and arranged to slide outwardly, a longitudinally extending bolt secured in each of said wings to one side of the radial line of movement of said wing, rotary cutters mounted on said bolt and means to limit the outward movement'of said wing on said arm.

2. A tube cleaner having a revoluble cutter head, comprising a body with radially projecting rectangularly shaped arms thereon, wings having a rectangular radial slot therethrough engaging said projecting arms and arranged to slide outwardly, a longitudinally extending bolt carrying rotatable cutters secured in each of said wing to one side of the radial line of movement of said wings and means to limit the outward movement of said wing on said arm.

3. A tube cleaner having a revoluble cutter head, comprising a body with radially projecting arms thereon, each arm being provided with a radially extending recess therein, a wing mounted on each of the projecting arms and arranged to slide outwardly, a longitudinally extending bolt carrying rotatable toothed cutters secured in each of said wings to one side of the radial line of movement of said Wing and means to limit the outward movement of said wing, said means consisting of a pin secured in said wing transversely to the axis of rotation and engaging the radially extending recess in said projecting arm.

4. A tube cleaner having a revoluble cutter outwardly thereon, .a longitudinally extending 5 bolt carrying rotatable toothed cutters secured in each of said wing to one side of the radial line of movement of said wing, a pin set transversely to the axis of rotation in said wing, the end of which engages the radially extending re- 10 cess in said projecting arm and means to hold lockingly said pin in said wing.

5. A tube cleaner having a revoluble cutter head, comprising a body with radially projecting arms thereon, each arm being provided with a 15 radially extending recess therein, a Wing mounted on each of said projecting arms and arranged to slide outwardly thereon, a longitudinally extending bolt carrying rotatable toothed cutters secured in each of said wing to one side of the radial 29 line of movement of said wing, a pin set in said wing transversely to the axis of rotation of said wing, the end of which engages the radially extending recess in said projecting arm and means to lockingly hold said pin in said wing. 25 3 i 6. A tube cleaner having a revoluble cutter head, comprising a body with radially projecting arms thereon, wings provided with a radial slot therethrough and radially extending groove rearwardly of said radial slot, said wing being slidably 3Q mounted on said projecting arm, a longitudinally extending bolt secured in each of said wings to one side of the radial line of movement of said wing, cutters rotatably mounted on bolts forwardly of said wing and in the radially extending groove 35';

in said Wing and means to limit the outward movement of said wing on said projecting arm.

'7. A tube cleaner having a revoluble cutter head, comprising a body having radially projecting rectangularly shaped arms thereon, each 40;:

arm being provided with a radially extending recess therein, wings slidably mounted on said projecting arms, each wing being provided with a radial slot therethrough and a radially extending groove rearwardly of said radial slot, a longi- 45 in the radially extending groove in said wing, 50

and means to limit the outward'movement of said wing'on said projecting arm, said means consisting of a pin set transversely in said wing to its axis of rotation and engaging the radial recess in said projecting arm. t 55 8. A tube cleaner having a revoluble cutter head, comprising a longitudinally extending body having radially projecting rectangularly shaped arms thereon, each arm having a radially extending recess therein, wings provided with a 60 radial slot therethrough and a radially extending groove rearwardly of said radial slot and arranged to slide outwardly and swing freely on said arm, a longitudinally extending bolt removably secured in each of said wings to one side of the 65 radial line of movement of said Wing, rotatable toothed cutters mounted on said bolt forwardly of said wing and rearwardly in the radially extending groove in said wing, a pin set transversely to the axis of rotation in said wing to engage the radial recess in said projecting arm, said pin having a circular groove engaging the threaded bolt in said wing substantially as described.

HARRISON L. STALEY. 75. 

